Keep reading for the spoilers:
When she returns in the Oct. 10 episode, it will once again be via Skype (Baranski’s Good Wife duties on the East Coast make in-person appearances difficult). It’s not clear what brings her back, but, given her special connection to Sheldon, one shouldn’t assume it’s her son she wants to see. Just putting that out there!
Source: TV Line
‘Big Bang Theory’ season 7 bows Thursday, Sept. 26 on CBS.